Extreme space weather events in March 1989, November 2003 and May 2024 and their associated hazard over Romanian territory

In the present study, the extreme space weather events in March 1989, November 2003 and May 2024, causing the most severe geomagnetic storms that occurred in the satellite era, are investigated from the point of view of the associated hazard, described in terms of the surface geoelectric field, which in turn can result in geomagnetically induced currents. The surface electric field at the scale of Romania, produced by the variable magnetic field of geomagnetic storms, is determined on the basis of Earth’s magnetic field records from the national geomagnetic observatory and information on the electrical conductivity of the underground. We show that the amplitude of geoelectric field depends on the morphology rather than the amplitude of the geomagnetic disturbance, and is significantly higher in case of March 1989 than in case of the other two events. The maps of the amplitude of the geoelectric field vector on the Romanian territory are presented, constituting the geoelectric hazard map at the country scale.